1. Field of the Invention
The present invention relates generally to electric compressors and, more specifically, to a horizontal type electric compressor formed by accommodating in a casing a compressor section and an electric motor for driving the same.
2. Description of the Related Art
In an electric compressor, the compressor is connected to a motor through a drive force transmitting portion, and is rotated by a drive force of the motor to compress fluid. The motor, the drive force transmitting portion, and the compressor section are accommodated as a unit in a casing.
As an electric compressor of this type, the applicant of the present invention has proposed in Japanese Patent Application No. 2002-55672 a horizontal type one as shown in FIG. 12.
In this electric compressor, a compressor section 20A and a motor 10 for driving the same are accommodated in a casing 2′. A motor rotor 16 is connected to an extension portion of a rotor shaft 27 of a compressor section 20, and the motor 10 is formed by a stationary stator 11 of the casing 2′ and the motor rotor 16.
When the compressor section 20A is driven by the motor 10, a refrigerant sucked in through a refrigerant suction port 7 flows through communication passages 54 of a suction chamber 50 and a narrow gap between the stator 11 and the motor rotor 16 of the motor 10 and is sucked into the compressor section 20A to be compressed therein and discharged into a discharge chamber 52 before being supplied to the exterior through a refrigerant discharge port 9.
Since the motor is cooled by the sucked refrigerant flowing around the motor 10, it is possible to improve the motor in terms of efficiency.
By the way, there are provided, for example, four communication passages 54 are in a circumferential direction of the stator 11, between the casing 2′ and the stator 11. However, the sectional areas of the refrigerant passages in the suction chamber 50, inclusive of these communication passages 54, are not uniform. Further, the pasages cannot help forming rather complicated routes. Thus, there are involved portions where the flow velocity of the refrigerant is lowered and portions where the refrigerant is allowed to stay.
In this case, the sucked refrigerant contains a minute amount of lubricant in the form of a mist, and this lubricant may gather at the bottom portion (lower portion) of the casing 2′, where the flow velocity is lowered or the refrigerant is allowed to stay as mentioned above.
In such a case, the lubricant has been removed from the refrigerant, which means a shortage of the lubricant entering the compressor section. Thus, there is no saying with assurance that the compressor is absolutely free from wear, heat generation, or adhesion due to insufficient lubrication, or a reduction in the amount of the refrigerant discharged due to insufficient sealing.